18 Velutina velutina. Sublittoral. Water temperature 3ºC. Norway. January 2013. © E. Svensen.

18 Velutina velutina. Sublittoral. Water temperature 3ºC. Norway. January 2013. © E. Svensen.

Mating, at 3ºC, by pair lying head-on, foot to foot, on their left sides so their right-side genitalia are adjacent. In the photo, the massively engorged penis of only one of them can be seen to be penetrating the other.

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